/*
    * Copyright (C) 2008 The Guava Authors
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.google.common.collect.testing.testers;
  
  import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_KEYS;
  import static com.google.common.collect.testing.features.MapFeature.ALLOWS_NULL_VALUES;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.collect.testing.AbstractMapTester;
  import com.google.common.collect.testing.Helpers;
  import com.google.common.collect.testing.features.CollectionSize;
  import com.google.common.collect.testing.features.MapFeature;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Map.Entry;
  
  /**
   * Tests {@link java.util.Map#equals}.
   *
   * @author George van den Driessche
   * @author Chris Povirk
   */
  @GwtCompatible
  public class MapEqualsTester<K, V> extends AbstractMapTester<K, V> {
    public void testEquals_otherMapWithSameEntries() {
      assertTrue(
          "A Map should equal any other Map containing the same entries.",
          getMap().equals(newHashMap(getSampleEntries())));
    }
  
    @CollectionSize.Require(absent = CollectionSize.ZERO)
    public void testEquals_otherMapWithDifferentEntries() {
      Map<K, V> other = newHashMap(getSampleEntries(getNumEntries() - 1));
      Entry<K, V> e3 = getSubjectGenerator().samples().e3;
      other.put(e3.getKey(), e3.getValue());
      assertFalse(
          "A Map should not equal another Map containing different entries.",
          getMap().equals(other)
      );
    }
  
    @CollectionSize.Require(absent = CollectionSize.ZERO)
    @MapFeature.Require(ALLOWS_NULL_KEYS)
    public void testEquals_containingNullKey() {
      Collection<Map.Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1);
      entries.add(entry(null, samples.e3.getValue()));
  
      resetContainer(getSubjectGenerator().create(entries.toArray()));
      assertTrue("A Map should equal any other Map containing the same entries,"
          + " even if some keys are null.",
          getMap().equals(newHashMap(entries)));
    }
  
    @CollectionSize.Require(absent = CollectionSize.ZERO)
    public void testEquals_otherContainsNullKey() {
      Collection<Map.Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1);
      entries.add(entry(null, samples.e3.getValue()));
      Map<K, V> other = newHashMap(entries);
  
      assertFalse(
          "Two Maps should not be equal if exactly one of them contains a null "
          + "key.",
          getMap().equals(other));
    }
  
    @CollectionSize.Require(absent = CollectionSize.ZERO)
    @MapFeature.Require(ALLOWS_NULL_VALUES)
    public void testEquals_containingNullValue() {
      Collection<Map.Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1);
      entries.add(entry(samples.e3.getKey(), null));
  
      resetContainer(getSubjectGenerator().create(entries.toArray()));
      assertTrue("A Map should equal any other Map containing the same entries,"
          + " even if some values are null.",
          getMap().equals(newHashMap(entries)));
    }
  
    @CollectionSize.Require(absent = CollectionSize.ZERO)
    public void testEquals_otherContainsNullValue() {
      Collection<Map.Entry<K, V>> entries = getSampleEntries(getNumEntries() - 1);
      entries.add(entry(samples.e3.getKey(), null));
      Map<K, V> other = newHashMap(entries);
  
     assertFalse(
         "Two Maps should not be equal if exactly one of them contains a null "
         + "value.",
         getMap().equals(other));
   }
 
   @CollectionSize.Require(absent = CollectionSize.ZERO)
   public void testEquals_smallerMap() {
     Collection<Map.Entry<K, V>> fewerEntries
         = getSampleEntries(getNumEntries() - 1);
     assertFalse("Maps of different sizes should not be equal.",
         getMap().equals(newHashMap(fewerEntries)));
   }
 
   public void testEquals_largerMap() {
     Collection<Map.Entry<K, V>> moreEntries
         = getSampleEntries(getNumEntries() + 1);
     assertFalse("Maps of different sizes should not be equal.",
         getMap().equals(newHashMap(moreEntries)));
   }
 
   public void testEquals_list() {
     assertFalse("A List should never equal a Map.",
         getMap().equals(Helpers.copyToList(getMap().entrySet())));
   }
 
   private static <K, V> HashMap<K, V> newHashMap(
       Collection<? extends Map.Entry<? extends K, ? extends V>> entries) {
     HashMap<K, V> map = new HashMap<K, V>();
     for (Map.Entry<? extends K, ? extends V> entry : entries) {
       map.put(entry.getKey(), entry.getValue());
     }
     return map;
   }
 }